Sabatieria parvamphis, Yang & Guo & Chen & Lin, 2019

Yang, Peipei, Guo, Yuqing, Chen, Yuzhen & Lin, Rongcheng, 2019, Four new free-living marine nematode species (Sabatieria) from the Chukchi Sea, Zootaxa 4646 (1), pp. 31-54 : 39-45

Sabatieria parvamphis sp. n.

( Figures 5–7, Tables 1, 3)

Type material. Five males and two females were collected from station CC 1.

Characters Sabatieria chukchensis sp. n. Sabatieria parvamphis sp. n.

Male Males Females Male Males Females

holotype Paratypes Paratypes holotype Paratypes Paratypes n - 4 2 - 4 2 Total body length 2323 2144±76 ( 2052–2263) 2228–2326 2473 2293±72 ( 2180–2378) 2472–2730 a 26 27±2 (25–29) 23–29 26 28±1 (26–29) 31–32

b 10 10±1 (8–10) 9– 10 8 9 (8–9) 9–10

c 14 14±1 (13–15) 13 12 11 (11–12) 11–12 Head diameter 17 16 (16–17) 17–18 18 18±1 (17–19) 17 Length of cephalic setae 5 5±1 (4–6) 6–7 6 6 (6–7) 6–7 Amphideal fovea from anterior end 7 7±1 (6–7) 5–6 8 9±1 (8–10) 8–9 Amphideal fovea diameter 11 11±1 (10–12) 10 13 13 ±1 (12–15) 11–12 Amphideal fovea diameter / corresponding body diameter (%) 61 62±4 (56–65) 53–55 69 66±5 (58–72) 55–62 Nerve ring from anterior end 136 113±7 (102–123) 130–138 157 149±5 (143–155) 147–153 Nerve ring / pharyngeal length (%) 59 51±5 (45–56) 55–56 52 56±2 (54–57) 54 Excretory pore from anterior end 142 130±6 (123–136) 141–147 193 168±5 (161–174) 172–177 Pharyngeal length 232 223±19 (205–254) 235–245 300 268±4 (264–273) 273–282 Pharyngeal end corresponding body diameter 62 65±5 (59–72) 59–80 77 69±1 (67–71) 64–65 Maximum body diameter 89 81±6 (73–89) 81–95 96 83±1(82–83) 81–86 Vulva from anterior end - - 1113–1178 - - 1221–1253 V (%) - - 50–51 - - 46–49 Spicule length along arc 73 70±1 (69–73) - 72 71±3 (67–74) - Spicule length along chord 57 55±2 (52–58) - 62 58±3 (54–62) - Gubernacular apophyses length 28 28±2 (25–30) - 30 30±1 (28–32) - Number of pre-cloacal supplements 7 7 - 13 15 - Anal or cloacal body diameter 55 52±5 (45–59) 47–58 58 54±4 (49–59) 47–50 Tail length 172 153±10 (142–164) 166–178 209 205±5 (197–209) 220–224 c’ 3.1 3.0±0.1 (2.8–3.2) 2.8–3.8 3.6 3.8±0.2 (3.5–4.0) 4.4–4.8

Species Total body length a Amphideal fovea diameter Cephalic setae Spicule arc length / Number of c’

/ corresponding body length / head cloacal body diameter pre-cloacal

diameter (%) diameter (%) supplements S. chukchensis sp. n. 2052–2323 25–29 56-65 27–34 1.2–1.6 7 2.8–3.2

S. maboyae 1410–1700 35–40 48–55 - 2.1 4–5 4.6–5.6

S. mortenseni 1900 47 80 80 1.0 6 3.2

S. pisinna 655 27 82–87 22 1.3 - 2.3–2.6

S. propisinna 670–710 30–35 77 43–44 1.3–1.4 - 3.2–3.7

S. pulchra 1900–2300 23–31 60 40–50 1.3–1.5 7–9 3.0–3.5

S. pumila 725–784 21–28 69–85 18 1.5–2.0 8–9 2.7–3.1

S. punctata 1095–1160 33–36 70 38–42 1.3 6 3.2–3.9

Species Total body length a Amphideal fovea diameter / Cephalic setae Spicule arc length / Number of c’ corresponding body length / head cloacal body pre-cloacal diameter (%) diameter (%) diameter supplements

S. parvamphis sp. n. 2180–2473 26–29 58–72 31–38 1.2–1.4 13–15 3.5–4.0

S. abyssalis 1650–1850 25–33 80 50–65 1.1–1.3 10 4.5

S. longisetosa 1310–1585 40 90 100 1.2–1.3 13–14 3.7–4.5

S. macramphis 1700–2120 52–61 84–93 140–170 1.0 18–21 4.5

S. ornata 1350–2080 35–47 78–98 40–57 1.0–1.3 10–18 4.6–5.9

S. stenocephalus 2162–2250 31–33 79–81 69–75 1.3–1.4 15 3.8–4.6

Holotype: ♂ 1 on slide number Chukchi20100720 CC14206 . Paratypes: ♂ 2 on slide number Chukchi20100720 CC14206 , ♂ 3 on Chukchi20100720 CC14203 , ♂ 4 on Chukchi20100720 CC14210 , ♂ 5 on Chukchi20100720 CC14211 , ♀ 1 on Chukchi20100720 CC14212 , ♀ 2 on Chukchi20100720 CC12207 .

Type locality and habitat. All specimens were collected from the Chukchi Sea ( 52 m water depth). Station CC 1: 67.6722°N, 168.9562°W. Median grain diameter: 5.35 Md Φ, Sand: 33.34%, Silt: 58.02%, Clay: 8.63%.

Etymology. The species name is derived from the latin parvus (=small) and amphis (=amphid), and refers to the small amphid in this species relative to other species of the ornata group.

Measurements. Table 1.

Description. Male. Body cylindrical, tapering slightly towards both extremities. Cuticle with transverse rows of dots, lateral differentiation consisting of larger, irregularly-spaced dots. Two dorso- and two ventro-lateral rows of short, sparse somatic setae. Three crowns of anterior sensilla: six inner labial papillae, six short but distinct outer labial setae and four short cephalic setae. Buccal cavity cup-shaped. Amphideal fovea spiral with 3.25 turns, located immediately posterior to cephalic setae. Pharynx gradually swelling towards posterior, not forming true bulb. Nerve ring 143–157 µm from anterior end of body, at 52–57% of the pharyngeal region length. Excretory pore 161–193 µm from anterior end of body, at 59–66% of the pharyngeal region length. Tail 197–209 µm long, conico-cylindrical with four rows of sparse short caudal setae and three short terminal setae. Reproductive system diorchic, with outstretched testes. Anterior testis to the left of intestine, posterior testis to the right of intestine. Spicules paired, equal, arcuate, equal to 1.2–1.4 cloacal body diameters in length. Gubernaculum with 28–32 µm long, with paired, curved apophyses. Thirteen to fifteen prominent tubular pre-cloacal supplements with distance between adjacent supplements increasing towards anterior, followed by one pre-cloacal seta. Three caudal glands situated posterior to spicule. Spinneret present.

Female. Similar to male, except for longer total body length and longer tail length. Reproductive system didelphic, ovaries opposed, outstretched, with anterior branch to the left of intestine and posterior branch to the right of intestine. Mature eggs are oval-shaped. Spermatheca not observed. Vulva located at 46–49% of the body length. Vaginal glands not observed, pars proximalis vaginae surrounded by constrictor muscle. Three caudal glands situated posterior to anus. Spinneret present.

Diagnosis and relationships. Sabatieria parvamphis sp. n. is characterized by short cephalic setae ( 6–7 µm, equal to 31–38% of head diameter), small amphideal fovea (equal to 55–72% corresponding body diameter), amphideal fovea spiral with 3.25 turns, curved gubernacular apophyses, thirteen to fifteen prominent tubular precloacal supplements with distance between adjacent supplements increasing towards the anterior, tail length equal to 3.5–4.8 cloacal body diameters.

Sabatieria parvamphis sp. n. belongs to the ornata group based on the presence of curved gubernacular apophyses, and pre-cloacal supplements with distance between adjacent supplements increasing towards the anterior. There are five valid species in this group now. S. parvamphis sp. n. can be differentiated from all other species of the group by relatively small amphideal fovea (equal to 55–72% corresponding body diameter) and short cephalic setae ( 6–7 µm, equal to 31–38% of head diameter). Besides, S. parvamphis sp. n. can be differentiated from S. macramphis and S. longisetosa by the length of cephalic setae (equal to 31–38% vs 140–170%; 100% head diameter, respectively). S. parvamphis sp. n. can be differentiated from S. abyssalis in the number of pre-cloacal supplements (13–15 vs 10). S. parvamphis sp. n. and S. stenocephalus can be distinguished according to body shape – in S. stenocephalus anterior part of the body is very sharp-pointed ( Huang & Zhang, 2006). S. parvamphis sp. n. resembles S. ornata in the number of pre-cloacal supplements and tail shape, but differs from it in longer total body length (2180–2730 vs 1350–2240 µm) and shorter tail (c’=3.5–4.0 vs 3.8–4.6).